Radio reproducing attachment for pianos



July 9, 1929. J. M. cam-E ET A L l1,720,542

' RADIO RPRODUCING ATTACHMENT FOR PIANos Filed June 18, T927 y E 24 E.

. Y v W X bo lNvENToRS,

a Z6 @WIG ZY 24 26a l I9 I T5@ w '1 o A Patented July 9, 1929. i

UNI-TED srrATEsA PATENT OFFICE. y

JOHN M. coo'rE AND CLARENCE E. rRYoR, 'or ELIZABETH, NEW JERSEY.i

RADIO REPRODUCING v.A'JETACHJYI152NT FOR PIANOS.

Application med June 1s,

This invention relates to radio reproducing attachment for pianosounding boards 4 and the like. i

Pursuant to our invention, the electrical radio' reproducingdeviceactuated by the radio receiving set is adjustably positionedrelatively to the sounding board of a piano, usually at the region ofengagement of the are reproduced effectively byfthe sounding boardvibrating as a whole.

It is usually convenient inl upright and grand types of pianos to attachour attachment to the rear of the sounding board.

Further features and objects ofthe invenf tion will be more fullyunderstood from the following detail description andthe accompanyingdrawings, in which Fig. 1 is an elevation of the rear of an upright.form of piano, showing. our radioreproducer attached thereto;

Fig. 2 is a sectional elevation on line 2- 2 of Fig. 1, on a greatlyenlarged scale;

Fig. 3' is a sectional elevation on line 3 3 of Fig. l; i

Fig. 4 is a sectional elevation on line 4-4 of Fig. 3, on an enlargedscale; l

Fig. 5 is a detail sectional elevation of certain parts;

Fig. 6 is a detail view of a modification; and Fig. 7 is a detail viewshowing the assembly of our invention in a grand piano.

Referring to the drawings, the piano 1() may be of any form, andincludes a suitable sounding board 11, associated with the usual treblebridge 12 disposed on the inner face of the sounding board, for locatingthe wires Corresponding to the keys of the piano; the key actuating anddamping parts are of the usual or any approved type. Y

In the instance of an upright piano, as il- `1327. serial No. 199,822.,

tending. from the bottomvrail -14 to the top 55 rail 15. f

It Visconvenient to attach our radio reproducer 16 between-two centralstanchions13, 13b, to locate the actuated element 17, see Figs. 2 and,3, of our radio reproducing device 16 60 in substantially horizontalalignment with the intersectionr of the bridge 12 with the soundingboard 11 between such' Vcentral stanchions 13, 13b; f

Usually, the sounding board ofa piano is held to the bridge by a button`18 which is secured by a screw or a dowel pin.. Such button ispreferably lof harder wood or other material than the sounding board.

An effective manner of assembly of our invention is had by removing thescrew, then' removing the button, then boring a hole 19 at the locationthrough the sounding` boa-rd and into the bridge, and then inserting adowel p pin. 20 of maple or like material, which pin 75 20 tightly iits'the bored hole. The pin 20 is glued fast in the bored hole. l Theaperture 21 is bored through substantially the center of the pin 20, butnot eX- teding entirely through the pin, thus leaving the solid bottomedportion 20. The but? Y e ton 18 is replaced and secured' by glue.

Any suitable `:t'orm of electrically actuated radio reproducing devicemay be employed, which comprises usually one or more voice coils 22, thewindings of which are connected with the terminals of the plug ory ofthe last audio stage of the radio receiving set, and also usuallycomprising an armature 23 which is vibrated in correspondence tovariatios of the electrical current passing through the windings of thevoice coils. Such radio reproducing device usually includes also apermanent magnet and a core controlling the range of movement of thearmature and the path of the electro-magnetic H ux created 4jointly bythe permanent magnet and the variatlons` of the current passing throughthe voice coils 22.

We have shown the vibrated member 24 approximately three-thirty secondsof an inch outer diameter. The free end of the member 24 is solderedaspindicated at 24 within the bored opening \2.6. The inner end 26".ofthe rod 26 is threaded to be screwed into the bore of the plug 27. The

bore of the plug 27 does not extend through the bottom of the plug 27.The leather plug serves to preclude contact at any location. between therod 26 and the pin 20. Generally speaking, the highest grades of leathergive best results and we have obtained optimum results bythe use of oaktanned leather of the back of the hide.

As is indicated in Figs. 2 and 3, our radio reproducing attachment isconveniently secured in position by means of a supporting and adjustingbar 28 extending between the stanchions13" and 13" and adjustablysecured thereto by means of the screws 29, 30

, passing through suitable openings in the bar Our radio reproducingattachment is assembled and adjusted by means of the screws 29, 30 andthe member 24 and rod 26 integrally connected to one another at the setposition, as above described, to locate the end 26" in firm engagementunder pressure with the leather shielding 27. Such adjustment is madewhile the movable or actuatable parts of the radio reproducing devicearequiescent and also to locate the armature to have free vibrationunder electro-magnetic actuation. Such relationship of the parts enablesthe screws 29, l30 to be further adjusted in their tapped'openings inthe braces 13, 13" if desired, or from time to time, loosened ortightened, to thereby correspondingly adust the bar 28 and therewith ourradio repro ucing unit 16, including its actuated members 24, 26,relative to the sounding board 11 and the bridge 12, for

attaining optimum reproduction and also for permitting a range ofvariation of' the emitted volume of the reproduced sounds.

Preferably, our radio reproducing unit 16 comprises a laminated core 31which is secured The armature 23 is preferably anchored lat its iixedend 23"L to a rigid support, such as the bar 35, in turn rigidly securedat its ends to the legs 32, 33 of the Ipermanent magnet 34, and theactuated member 24 is secured to the to and extends from one leg32 tothe yopposite leg 33 of'a permanent magnet 34.

armature 23 at a location between its fixed end 23 and its free eiid.Such rigid support bar 35 ma advantageously be subject to adjustment yemploying the 4screw-threaded member having a thumb-head 36 for exertinga twist on the bar 36 within ranges of high pressure per square inch,thus attaining an adjustment imposing high compression on the bar 35 andmaintaining the bar 35 rigid for every adjusted position.

Preferably, when our invention is applied to the rear or otherinaccessible part of the piano or like instrument, we provide a rod orarm 37 extending at its free end 38 to the side or other readilyaccessible portion of the piano and attached at its opposite end tothethumb-head 36 or equivalent, to enable theA adjusting member 36 to heregulated by pushing and pulling from time to time to any desired setosition. The free end 38 of the rod 37 may e loosely passed through `a,screweye 40 or equivalent.

The clamping and regulating bar 28 may advantageously be standardizedand pro-- vided with a plurality of pairs of openings 41 and 42, 41a and42a, 41" and 42", etc., for varying positions of the set bolts 43, 44,or equivalent of the lradio reproducing unit, to accommodate readyvariable positions of the unit relative to the treble bridge or otherlocation with respect to the sounding board, and for dierent makes andtypes of pianos.

In Fig. 6, we have shown a modification of screw-threading the free endof the wire 24 and providing reverse-threading at the abutting end ofthe wire 26, and employing a turn-buckle 50 to adjust the iinalposition. The wire 24 is soldered to the turn-buckle 50 at final4setting as indicated at 51 and similarly at 52 to solder the wire 26 tothe turnbuckle 50.

In Fig. 7, ,we show, our invention applied to a grand type of'piano inwhich the sounding board 11 is in horizontal position." In thisinstance, the plug 21 is inserted from the bottom similarly'as in anupright type o piano, and an opening 53 is drilled through the bridge ofsmaller diameter than the opening 19. The wire or rod `26 is passedthrough the opening 53 and brought into damped securement within' theleather plug 27, similarly as hereinabove set forth.

The thickness of the leather shielding 27 filo intervening between theactuated member 26 and the maple pin or equivalent should be of themagnitude of one-sixteenth of an inch 0r less to thereby provide for .asuiiiciently firm operating connection between the recipi rocallyactuated member 26 and the pin, which operating connection. in bothdirections of reciprocatory action' is enhanced by the leather shielding27.

Whereas, we have described our invention by reference to specific formsthereof, 1t wlll be understood that many changes and modi-r ications maybe made without departing from the spirit of the invention.

We claim:

1. The combination. with a sounding board of a piano or the like,including elements for supporting the sounding board andfurther includina bridge for said sounding board, said bri ge being provided with abottomed recess, of an electro-magnetic device comprising coil means, anarmature responsive to the variations of the current passing through thewindin of said coil means, an element actuated y said armature, meansfor support-v ing said electro-ma etic device on said supportingelements, t e free end of said actuated element being disposed underpressure within said'bottomed recess, and means for adjusting the degreeof pressure between vsa'id actuated element and said bridge.

2. The combination with a sounding board of a piano or the like,including elements for supporting'the sounding board and furtherincludin a bridge 'for said soundingboard, said bri ge being providedwith a bottomed recess, of an electro-magnetic device comprising coilmeans, an armature responsive to the variations of the current 4passingthrough the winding of said coil means, a core for said coil means,means for adjusting the normal clearance between sald armature'and .saidcore, an element actuated by said armature, means for supporting saidelectro-magnetic device on said supporting elements, the free end ofsaid actuated element being disposed under tomed recess, an the meansfor adjustin degree of pressure between said actuatev element and saidbridge.

i 3. The combination with a soundingboard of a piano or the like,includin elements for supporting the sounding boar and further includina bridge for said sounding board, said bri e being provided with abottomed recess, oig an electro-magnetic v vdevice comprising coilmeans, an armature responsive to the variations of the current passingthrough the winding of said coil means, a core for sald coil means,compressional means for adjusting the normal clearance between saidarmature and said core, an element actuated b said armature, means forsupporting said elsectro-magnetic device on said supporting elements,`the free end of 'said actuated element being disposed under pressurewithin said bottomed recess, and means for ad'ust- `ing the degree ofpressure between sai ac` tuated element and said bridge.

4. The combination with a sounding board of a piano or the like,including elements for supporting the sounding board, of anelectromagnetic device comprismg coil means, an armature responsive tothe varlations of the current passing through the windlng of said coilmeans, an element actuated by said armaments, said sounding board belngwith la bottomed recess, a lplugv o sounding board. Y

6. The combination with a sounding board ressure within said bot-ytura-means for supporting 'said electro-mag- 1 .rial disposed atthebottom of said bottomed recess,the free end of said actuated elementbeing in contact under pressure with said disk, and means for adjustingthe degree of pressure between said actuated element and said soundinboard. y

5. vThe com ination with a sounding board of a piano or the like,including elements for supporting the sounding board, of anelectro-magnetic device comprising coil means, an armature responsive tothe variations .of the current passing through the winding of said coilmeans, an element actuated by said armature, means for supporting saidelectro-magnetic device on said supporting elerovided leather disposedat the bottom of said bottomed recess, the free end of said actuatedelement being in contact .under pressure with said disk, and'means foradjusting the degree of pressure between `said actuated-element and saidof a piano or the like, including elements for supporting thesounding-board, and further including a bridge for said sounding board,

said bridge being provided with ya bottomed recess, of anelectro-magnetic devicel com-A prising coil means, an element actuatedby said coil means, means for Vsupporting said electra-magnetic deviceon sald supporting elements, a plug of resilient-dense material loo edisposed at the bottom of said bottomed recess, the freeend ofsaidactuated element being disposed underpressure against said plug, andmeansfor adjusting the degree of pressure between said actuated elementand said plug.

7. The combination'with asounding board ofa piano and the like,including a bridge and associated elements for supporting thesoundingboard, said brid e being rovided with a bottomed recess su stantial y atthe location of the passage overv the brid e of the wires correspondingto the'middle tone, o an electro-magnetic device comprising coil means,an armature responsive to the variations of the current passing throughthe winding 'of said coil means, an element actuated y said armature,means for supporting said electro-magnetic device, the free end of saidactuated element being disposed under pressure within said bottomedrecess,

and means for adjusting the degree of pres- .sure between said actuatedelement and said bridge.

8. The combination with a sounding board j of a piano and the likeincluding a bridge and associated elements for supportlng-the soundingboard, of an electro-magnetic device com prising eoilv me'anganJarmature responsive of said actuated kelement being disposed uri-"10 tothe Variations-dof the current passing der pressure against saidsounding board through the winding;v of saidgcoil means, an and saidbridge, and means oradjustin the element actuated `by-fsaid armature,means degree of pressure betweehisaid actuate ele- 5 forsupporting saidelectro-magnetic device nient and said bridge` l to locate saidactuatedelement in Contact with In testimony whereof We have signed thisl15 said sounding boardy corresponding to the specification this 16thday of June,';1927. looationof the'passing over said `bridge of v I JOHNM CO TE. the wiresv of the middle C tone, the free end CLARENCE PRYOR.

